Rare 1920s Art Deco antique AT&T Telephone Numbers miniature book pendant brooch

Incredible piece of telecommunications and jewelry history. Great condition, shows some rubbing to gold gilding throughout however has retained perfect structure and functionality. Features a molded metal leaf brooch upper with C-catch. Book pendant can be removed from brooch and contains 10 individual pages (20 if front and back are counted) with previous owner's phone numbers, precious tiny drawings, and addresses. It is interesting to note the early alphanumeric exchange system phone number formatting consisting of combinations of letters followed by five digits-first seen in 1917 and in widespread use in the United States from the 1920s all the way up to the midcentury. The inside front page bears the 1920s-era Bell System Logo encircled by text reading "New England Telephone & Telegraph Co" and "American Telephone & Telegraph Co". Book clasps closed securely. Please see photos for measurements in inches.